A mountain is a large landform that stretches above the surrounding land in a limited area, usually in the form of a peak. A mountain is steeper than a hill. Mountains are formed through tectonic forces or volcanism and these forces can locally raise the surface of the earth. Mountains erode slowly through the action of rivers, weather conditions, a few mountains are isolated summits, but most occur in huge mountain ranges. High elevations on mountains produce colder climates than at sea level and these colder climates strongly affect the ecosystems of mountains, different elevations have different plants and animals. Because of the less hospitable terrain and climate, mountains tend to be used less for agriculture and more for resource extraction and recreation, the highest mountain on Earth is Mount Everest in the Himalayas of Asia, whose summit is 8,850 m above mean sea level. The highest known mountain on any planet in the Solar System is Olympus Mons on Mars at 21,171 m, there is no universally accepted definition of a mountain.
Elevation, relief, steepness and continuity have been used as criteria for defining a mountain, whether a landform is called a mountain may depend on local usage. The highest point in San Francisco, California, is called Mount Davidson, notwithstanding its height of 300 m, Mount Scott outside Lawton, Oklahoma is only 251 m from its base to its highest point. Whittows Dictionary of Physical Geography states Some authorities regard eminences above 600 metres as mountains, in addition, some definitions include a topographical prominence requirement, typically 100 or 500 feet. For a while, the US defined a mountain as being 1,000 feet or taller, any similar landform lower than this height was considered a hill. However, the United States Geological Survey concludes that these terms do not have technical definitions in the US, using these definitions, mountains cover 33% of Eurasia, 19% of South America, 24% of North America, and 14% of Africa. As a whole, 24% of the Earths land mass is mountainous, there are three main types of mountains, volcanic and block.
All three types are formed from plate tectonics, when portions of the Earths crust move, compressional forces, isostatic uplift and intrusion of igneous matter forces surface rock upward, creating a landform higher than the surrounding features. The height of the feature makes it either a hill or, if higher and steeper, major mountains tend to occur in long linear arcs, indicating tectonic plate boundaries and activity. Volcanoes are formed when a plate is pushed below another plate, at a depth of around 100 km, melting occurs in rock above the slab, and forms magma that reaches the surface. When the magma reaches the surface, it builds a volcanic mountain. Examples of volcanoes include Mount Fuji in Japan and Mount Pinatubo in the Philippines, the magma does not have to reach the surface in order to create a mountain, magma that solidifies below ground can still form dome mountains, such as Navajo Mountain in the US
A mound is a heaped pile of earth, sand, rocks, or debris. Most commonly, mounds are earthen formations such as hills and mountains, a mound may be any rounded area of topographically higher elevation on any surface. Artificial mounds have been created for a variety of reasons throughout history, including ceremonial, burial, in the archaeology of the United States and Canada, a mound is a deliberately constructed elevated earthen structure or earthwork, intended for a range of potential uses. In European and Asian archaeology, the word tumulus may be used as a synonym for an artificial hill, while the term mound may be applied to historic constructions, most mounds in the United States are pre-Columbian earthworks, built by Native American peoples. Native Americans built a variety of mounds, including flat-topped pyramids or cones known as mounds, rounded cones. Some mounds took on unusual shapes, such as the outline of cosmologically significant animals and these are known as effigy mounds.
Some mounds, such as a few in Wisconsin, have rock formations, or petroforms within them, on them, while these mounds are perhaps not as famous as burial mounds, like their European analogs, Native American mounds have a variety of other uses. While some prehistoric cultures, like the Adena culture, used preferentially for burial, others used mounds for other ritual and sacred acts. The platform mounds of the Mississippian culture, for example, may have supported temples, the houses of chiefs, council houses, other mounds would have been part of defensive walls to protect a certain area. The Hopewell culture used mounds as markers of complex astronomical alignments related to ceremonies and related earthworks are the only significant monumental construction in pre-Columbian Eastern and Central North America. Mounds are given different names depending on which culture they strive from and they can be located all across the world in spots such as Asia and the Americas. Mound builders have more commonly associated with the mounds in the Americas.
They all have different meanings and sometimes are constructed as animals, kankali Tila is a famous mound located at Mathura in the Indian state of Uttar Pradesh. A Jain stupa was excavated here in 1890-91 by Dr. Fuhrer, mound, as a technical term in archaeology, is not generally in favor in the rest of the world. More specific local terminology is preferred, and each of these terms has its own article
In earth science, erosion is the action of surface processes that remove soil, rock, or dissolved material from one location on the Earths crust, transport it away to another location. Eroded sediment or solutes may be transported just a few millimetres, the rates at which such processes act control how fast a surface is eroded. Feedbacks are possible between rates of erosion and the amount of eroded material that is carried by, for example. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, while erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the rate of erosion in the region. Excessive erosion causes both on-site and off-site problems, on-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers.
In some cases, the end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of bodies, as well as sediment-related damage to roads. Intensive agriculture, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, and the surface runoff which may result from rainfall, produces four types of soil erosion, splash erosion, sheet erosion, rill erosion. Splash erosion is generally seen as the first and least severe stage in the erosion process. In splash erosion, the impact of a falling raindrop creates a crater in the soil. The distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rate is greater than the rate at which water can infiltrate into the soil.
If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope, sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically of the order of a few centimetres or less and this means that rills exhibit hydraulic physics very different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow
Topography is the study of the shape and features of the surface of the Earth and other observable astronomical objects including planets and asteroids. The topography of an area could refer to the shapes and features themselves. This field of geoscience and planetary science is concerned with detail in general, including not only relief but natural and artificial features. This meaning is common in the United States, where topographic maps with elevation contours have made topography synonymous with relief. The older sense of topography as the study of place still has currency in Europe, topography in a narrow sense involves the recording of relief or terrain, the three-dimensional quality of the surface, and the identification of specific landforms. This is known as geomorphometry, in modern usage, this involves generation of elevation data in digital form. It is often considered to include the representation of the landform on a map by a variety of techniques, including contour lines, hypsometric tints.
The term topography originated in ancient Greece and continued in ancient Rome, the word comes from the Greek τόπος and -γραφία. In classical literature this refers to writing about a place or places, in Britain and in Europe in general, the word topography is still sometimes used in its original sense. Detailed military surveys in Britain were called Ordnance Surveys, and this term was used into the 20th century as generic for topographic surveys, the earliest scientific surveys in France were called the Cassini maps after the family who produced them over four generations. The term topographic surveys appears to be American in origin, the earliest detailed surveys in the United States were made by the “Topographical Bureau of the Army, ” formed during the War of 1812, which became the Corps of Topographical Engineers in 1838. In the 20th century, the term started to be used to describe surface description in other fields where mapping in a broader sense is used. An objective of topography is to determine the position of any feature or more generally any point in terms of both a horizontal coordinate system such as latitude and altitude, identifying features, and recognizing typical landform patterns are part of the field.
There are a variety of approaches to studying topography, which method to use depend on the scale and size of the area under study, its accessibility, and the quality of existing surveys. Work on one of the first topographic maps was begun in France by Giovanni Domenico Cassini, in areas where there has been an extensive direct survey and mapping program, the compiled data forms the basis of basic digital elevation datasets such as USGS DEM data. This data must often be cleaned to eliminate discrepancies between surveys, but it forms a valuable set of information for large-scale analysis. The original American topographic surveys involved not only recording of relief, remote sensing is a general term for geodata collection at a distance from the subject area. Besides their role in photogrammetry and satellite imagery can be used to identify and delineate terrain features, certainly they have become more and more a part of geovisualization, whether maps or GIS systems
Morphometrics or morphometry refers to the quantitative analysis of form, a concept that encompasses size and shape. Morphometrics can be used to quantify a trait of evolutionary significance, a major objective of morphometrics is to statistically test hypotheses about the factors that affect shape. Morphometrics, in the sense, is used to precisely locate certain areas of organs such as the brain. Three general approaches to form are usually distinguished, traditional morphometrics, landmark-based morphometrics, traditional morphometrics analyzes lengths, masses, angles and areas. In general, traditional data are measurements of size. A drawback of using many measurements of size is that most will be correlated, as a result. For instance, tibia length will vary with femur length and with humerus and ulna length, traditional morphometric data are nonetheless useful when either absolute or relative sizes are of particular interest, such as in studies of growth. These data are useful when size measurements are of theoretical importance such as body mass and limb cross-sectional area.
However, these measurements have one important limitation, they contain information about the spatial distribution of shape changes across the organism. They are useful when determining the extent to which certain pollutants have affected an individual and these indices include the hepatosomatic index, gonadosomatic index and the condition factors. For example, where two specific sutures intersect is a landmark, as are intersections between veins on a wing or leaf, or foramina, small holes through which veins. Finding enough landmarks to provide a description of shape can be difficult when working with fossils or easily damaged specimens. That is because all landmarks must be present in all specimens, the data for each individual consists of a configuration of landmarks. There are three recognized categories of landmarks, type 2 landmarks are intermediate, this category includes points such as the tip structure, or local minima and maxima of curvature. They are defined in terms of features, but they are not surrounded on all sides.
In addition to landmarks, there are semilandmarks, points whose position along a curve is arbitrary, shape analysis begins by removing the information that is not about shape. By definition, shape is not altered by translation, scaling or rotation, thus, to compare shapes, the non-shape information is removed from the coordinates of landmarks. There is more one way to do these three operations
A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, the sea is the system of Earths salty. The sea moderates Earths climate and has important roles in the cycle, carbon cycle. Although the sea has been traveled and explored since prehistory, the scientific study of the sea—oceanography—dates broadly to the British Challenger expedition of the 1870s. Owing to the present state of continental drift, the Northern Hemisphere is now equally divided between land and sea but the South is overwhelmingly oceanic. Salinity in the ocean is generally in a narrow band around 3. 5% by mass, although this can vary in more landlocked waters, near the mouths of large rivers. About 85% of the solids in the sea are sodium chloride. Deep-sea currents are produced by differences in salinity and temperature, surface currents are formed by the friction of waves produced by the wind and by tides, the changes in local sea level produced by the gravity of the Moon and Sun.
The direction of all of these is governed by surface and submarine land masses, former changes in sea levels have left continental shelves, shallow areas in the sea close to land. The most diverse areas surround great tropical coral reefs, whaling in the deep sea was once common but whales dwindling numbers prompted international conservation efforts and finally a moratorium on most commercial hunting. Life may have started there and aquatic microbial mats are generally credited with the oxygenation of Earths atmosphere, the sea is an essential aspect of human trade, mineral extraction, and power generation. It is the scene of activities including swimming, surfing. However, population growth, industrialization, and intensive farming have all contributed to marine pollution. Atmospheric carbon dioxide is being absorbed in increasing amounts, lowering its pH in a known as ocean acidification. The shared nature of the sea has made overfishing an increasing problem, both senses of sea date to Old English, the larger sense has required a definite article since Early Middle English.
Seas are generally larger than lakes and contain salt water, while the defining elements of size and being bounded are generally used, there is no formally accepted technical definition of sea among oceanographers. In international law, the United Nations Convention on the Law of the Sea states that all the ocean is the sea. Earth is the known planet with seas of liquid water on its surface, although Mars possesses ice caps
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers. The stratum is the unit in a stratigraphic column and forms the basis of the study of stratigraphy. Each layer is one of a number of parallel layers that lie one upon another. They may extend over hundreds of thousands of kilometers of the Earths surface. Strata are typically seen as bands of different colored or differently structured material exposed in cliffs, road cuts, individual bands may vary in thickness from a few millimeters to a kilometer or more. Each band represents a mode of deposition, river silt, beach sand, coal swamp, sand dune, lava bed. Geologists study rock strata and categorize them by the material of beds, each distinct layer is typically assigned to the name of sheet, usually based on a town, mountain, or region where the formation is exposed and available for study. For example, the Burgess Shale is an exposure of dark, occasionally fossiliferous.
Slight distinctions in material in a formation may be described as members, formations are collected into groups while groups may be collected into supergroups. Archaeological horizon Geologic formation Geologic map Geologic unit Law of superposition Bed GeoWhen Database
Underwater refers to the region below the surface of water where the water exists in a natural feature such as an ocean, lake, pond, or river. Three quarters of the planet Earth is covered by water, a majority of the planets solid surface is abyssal plain, at depths between 4,000 and 5,500 metres below the surface of the oceans. The solid surface location on the planet closest to the centre of the orb is the Challenger Deep, but it can be explored by sonar, or more directly via manned or autonomous submersibles. An immediate obstacle to human activity under water is the fact that human lungs cannot naturally function in this environment, unlike the gills of fish, human lungs are adapted to the exchange of gases at atmospheric pressure, not liquids. Air is around 21% O2, water typically is less than 0. 001% dissolved oxygen, the density of water causes problems that increase dramatically with depth. The atmospheric pressure at the surface is 14.7 pounds per inch or around 100 kPa. A comparable water pressure occurs at a depth of only 10 m, thus, at about 10 m below the surface, the water exerts twice the pressure on the body as air at surface level.
For solids and liquids like bone and blood, this pressure is not much of a problem. This is because the air in those spaces reduces in volume when under pressure and so does not provide those spaces with support against the higher outside pressure. Even at a depth of 8 ft underwater, an inability to equalize air pressure in the ear with outside water pressure can cause pain. The danger of damage is greatest in shallow water because the ratio of pressure change is greatest near the surface of the water. For example, the increase between the surface and 10 m is 100%, but the pressure increase from 30 m to 40 m is only 25%. Any object immersed in water is provided with a buoyant force that counters the force of gravity, if the overall density of the object exceeds the density of water, the object sinks. If the overall density is less than the density of water, with increasing depth underwater, sunlight is absorbed, and the amount of visible light diminishes. Because absorption is greater for long wavelengths than for short wavelengths, white objects at the surface appear bluish underwater, and red objects appear dark, even black.
Although light penetration will be less if water is turbid, in the clear water of the open ocean less than 25% of the surface light reaches a depth of 10 m. At 100 m the light present from the sun is normally about 0. 5% of that at the surface, the euphotic depth is the depth at which light intensity falls to 1% of the value at the surface. This depth is dependent upon water clarity, being only a few metres underwater in a turbid estuary, at the euphotic depth, plants have no net energy gain from photosynthesis and thus cannot grow
In geography, a plain is a flat, sweeping landmass that generally does not change much in elevation. Plains occur as lowlands along the bottoms of valleys or on the doorsteps of mountains, as coastal plains, and as plateaus or uplands. In a valley, a plain is enclosed on two sides but in other cases a plain may be delineated by a complete or partial ring of hills, where a geological region contains more than one plain, they may be connected by a pass. Coastal plains would mostly rise from sea level until they run into elevated features such as mountains or plateaus, plains are one of the major landforms on earth, where they are present on all continents, and would cover more than one-third of the world’s land area. Plains may have formed from flowing lava, deposited by water, wind, or formed by erosion by these agents from hills. Plains would generally be under the grassland, savannah or tundra biomes, in a few instances and rainforests can be plains. Structural plains are relatively undisturbed horizontal surfaces of the Earth and they are structurally depressed areas of the world that make up some of the most extensive natural lowlands on the Earths surface.
Erosional plains have been leveled by various agents of such as running water, rivers and glacier which wear out the rugged surface. Plain resulting from the action of these agents of denudation are called peneplains while plains formed from wind action are called pediplains, depositional plains formed by the deposition of materials brought by various agents of transportation such as rivers, wind and glaciers. Their fertility and economic relevance depend greatly on the types of sediments that are laid down, flood plain, adjacent to a stream, lake or wetland that experiences occasional or periodic flooding. Scroll plain, a plain through which a river meanders with a low gradient. Lacustrine plain, a plain that originally formed in a lacustrine environment, lava plain, formed by sheets of flowing lava. Glacial plains, formed by the movement of glaciers under the force of gravity, sandar consist mainly of stratified gravel and sand. Till plain, a plain of glacial till that forms when a sheet of ice becomes detached from the body of a glacier.
Till plains are composed of unsorted material of all sizes, abyssal plain, a flat or very gently sloping area of the deep ocean basin. Planitia, the Latin word for plain, is used in the naming of plains on extraterrestrial objects, such as Hellas Planitia on Mars or Sedna Planitia on Venus
The Appalachian Mountains, often called the Appalachians, are a system of mountains in eastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period and it once reached elevations similar to those of the Alps and the Rocky Mountains before naturally occurring erosion. The Appalachian chain is a barrier to east-west travel, as it forms a series of alternating ridgelines, definitions vary on the precise boundaries of the Appalachians. A common variant definition does not include the Adirondack Mountains, which belong to the Grenville Orogeny and have a different geological history from the rest of the Appalachians. The range covers parts of the islands of Saint Pierre and Miquelon, the system is divided into a series of ranges, with the individual mountains averaging around 3,000 ft. The highest of the group is Mount Mitchell in North Carolina at 6,684 feet, the term Appalachian refers to several different regions associated with the mountain range.
Most broadly, it refers to the mountain range with its surrounding hills. The Ouachita Mountains in Arkansas and Oklahoma were originally part of the Appalachians as well, the name was soon altered by the Spanish to Apalachee and used as a name for the tribe and region spreading well inland to the north. Pánfilo de Narváezs expedition first entered Apalachee territory on June 15,1528, now spelled Appalachian, it is the fourth-oldest surviving European place-name in the US. After the de Soto expedition in 1540, Spanish cartographers began to apply the name of the tribe to the mountains themselves. The first cartographic appearance of Apalchen is on Diego Gutierrezs map of 1562, the name was not commonly used for the whole mountain range until the late 19th century. A competing and often more popular name was the Allegheny Mountains, Alleghenies, in the early 19th century, Washington Irving proposed renaming the United States either Appalachia or Alleghania. In U. S. dialects in the regions of the Appalachians.
In northern parts of the range, it is pronounced /ˌæpəˈleɪtʃᵻnz/ or /ˌæpəˈleɪʃᵻnz/, the third syllable is like lay. There is often debate between the residents of the regions as to which pronunciation is the more correct one. Elsewhere, a commonly accepted pronunciation for the adjective Appalachian is /ˌæpəˈlætʃiən/, the whole system may be divided into three great sections, The northern section runs from the Canadian province of Newfoundland and Labrador to the Hudson River. The Monteregian Hills, which cross the Green Mountains in Quebec, are unassociated with the Appalachians, The central section goes from the Hudson Valley to the New River running through Virginia and West Virginia. Southern, The southern section runs from the New River onwards and it consists of the prolongation of the Blue Ridge, which is divided into the Western Blue Ridge Front and the Eastern Blue Ridge Front, the Ridge-and-Valley Appalachians, and the Cumberland Plateau
Argentina, officially the Argentine Republic, is a federal republic in the southern half of South America. With a mainland area of 2,780,400 km2, Argentina is the eighth-largest country in the world, the second largest in Latin America, and the largest Spanish-speaking one. The country is subdivided into provinces and one autonomous city, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system, Argentina claims sovereignty over part of Antarctica, the Falkland Islands, and South Georgia and the South Sandwich Islands. The earliest recorded presence in the area of modern-day Argentina dates back to the Paleolithic period. The country has its roots in Spanish colonization of the region during the 16th century, Argentina rose as the successor state of the Viceroyalty of the Río de la Plata, a Spanish overseas viceroyalty founded in 1776. The country thereafter enjoyed relative peace and stability, with waves of European immigration radically reshaping its cultural.
The almost-unparalleled increase in prosperity led to Argentina becoming the seventh wealthiest developed nation in the world by the early 20th century, Argentina retains its historic status as a middle power in international affairs, and is a prominent regional power in the Southern Cone and Latin America. Argentina has the second largest economy in South America, the third-largest in Latin America and is a member of the G-15 and it is the country with the second highest Human Development Index in Latin America with a rating of very high. Because of its stability, market size and growing high-tech sector, the description of the country by the word Argentina has to be found on a Venice map in 1536. In English the name Argentina probably comes from the Spanish language, however the naming itself is not Spanish, Argentina means in Italian of silver, silver coloured, probably borrowed from the Old French adjective argentine of silver > silver coloured already mentioned in the 12th century. The French word argentine is the form of argentin and derives of argent silver with the suffix -in.
The Italian naming Argentina for the country implies Argentina Terra land of silver or Argentina costa coast of silver, in Italian, the adjective or the proper noun is often used in an autonomous way as a substantive and replaces it and it is said lArgentina. The name Argentina was probably first given by the Venitian and Genoese navigators, in Spanish and Portuguese, the words for silver are respectively plata and prata and of silver is said plateado and prateado. Argentina was first associated with the silver mountains legend, widespread among the first European explorers of the La Plata Basin. The first written use of the name in Spanish can be traced to La Argentina, a 1602 poem by Martín del Barco Centenera describing the region, the 1826 constitution included the first use of the name Argentine Republic in legal documents. The name Argentine Confederation was used and was formalized in the Argentine Constitution of 1853. In 1860 a presidential decree settled the name as Argentine Republic
Guilin, formerly romanized as Kweilin, is a prefecture-level city in the northeast of Chinas Guangxi Zhuang Autonomous Region. It is situated on the west bank of the Li River and its name means Forest of Sweet Osmanthus, owing to the large number of fragrant sweet osmanthus trees located in the city. The city has long been renowned for its scenery of karst topography and is one of Chinas most popular tourist destinations, in 314 BC, a small settlement was established along the banks of the Li River. During the Qin Dynastys campaigns against the state of Nanyue, the first administration was set up in the area around Guilin. In 111 BC, during the reign of Emperor Wu of the Han Dynasty, Shi An County was established, in AD507, the town was renamed Guizhou. Guilin prospered in the Tang and Song dynasties but remained a county, the city was a nexus between the central government and the southwest border, and it was where regular armies were placed to guard that border. Canals were built through the city so that supplies could be directly transported from the food-productive Yangtze plain to the farthest southwestern point of the empire.
In 1921, Guilin became one of the headquarters of the Northern Expeditionary Army led by Dr. Sun Yat-sen, in 1940, the city acquired its present name. Guilin administers seventeen county-level divisions, including six districts, nine counties and it has a total area of 27,809 square kilometres. The topography of the area is marked by karst formations, the Li River flows through the city. Winter begins dry but becomes progressively wetter and cloudier, spring is generally overcast and often rainy, while summer continues to be rainy though is the sunniest time of year. The monthly 24-hour average temperature ranges from 7.9 °C in January to 28.0 °C in July, and the annual mean is 18.84 °C. The annual rainfall is just above 1,900 mm, and is delivered in bulk from April to June, with monthly percent possible sunshine ranging from 14% in March to 53% in September, the city receives 1,487 hours of bright sunshine annually. Population,4,747,963 Urban population,975,638 Ethnic groups, Yao, Miao and Dong The GDP per capita was ¥19435 in 2009, ranked no.125 among 659 Chinese cities.
However, since the 1950s Guilin has electronics and agricultural equipment, medicine and buses, food processing, including the processing of local agricultural produce, remains the most important industry. More recent and modern industry feature high technology and the tertiary industry characterized by tourism trading, the airport is Guilin Liangjiang International Airport. Arriving to North Station, high-speed trains between Guilin and Changsha and Beijing came into operation in December 2013, in December 2014, high-speed operations began connecting Guangzhou, Shenzhen and Shanghai. It will bring much convenience for people come to Guilin and it takes only about 2 or 3 hours from Guangzhou to Guilin,7 hours from Shanghai to Guilin and 11 hours from Beijing to Guilin